BHN - RETNURN “CIRCULT, 53 
ceeded by the trolley and feeder copper,-raising the ratio to 
equality. A double track, of course, improves matters. We 
may tabulate these results somewhat as follows, calling Rt 
the track resistance and R the overhead resistance. 
Rt— 110 .2R. Exceedingly good track and very 
light load. 
N .2to .3R. Good track and moderate load. 
R — 4to .6 R. Tair track, moderatedoad, 
R! == 2to .3 R. Exceptional track and large sys- 
tem. 
R — 140 7 R. Good frack, large systetn. 
Rt = .7to 1.0 R.  Poor track, large system. 
In cases now somewhat exceptional the track resist- 
ance may exceed the overhead resistance considerably. The 
Drop-Volts 
  
Return circuit Street Railway Journal, 
F1c. 36. 
assumption now frequently made, that the track resistance 
is one-quarter that of the overhead system really repre- 
sents a better state of things than usually exists. To 
justify it requires the combination of continuous rail or 
exceptionally perfect bonding, with conditions of load that 
do not require large feeder capacity. Under the ordinary 
conditions R!=.4R is probably nearer the truth. The 
proportion between R and R? has, of course, a very im- 
portant bearing on the design of the overhead system. If 
the return circuit had no resistance then the entire drop